APOCYNACEAE - TheBackCountry

APOCYNACEAE

Apocynaceae is a family of flowering plants that includes trees, shrubs, herbs, stem succulents, and vines, commonly called the dogbane family, after the American plant known as dogbane, Apocynum cannabinum. Members of the family are native to European, Asian, African, Australian, and American tropics or subtropics, with some temperate members.

Many species are tall trees found in tropical rainforests, but some grow in tropical dry (xeric) environments. Also perennial herbs from temperate zones occur. Many of these plants have milky latex, and many species are poisonous if ingested. Some genera of Apocynaceae, such as Adenium, have milky latex apart from their sap, and others, such as Pachypodium, have clear sap and no latex.

Leaves are simple and  may appear singly with each occurrence on alternating sides of the stem (alternate), but usually occur in pairs or in whorls. When paired, they occur on opposite sides of the stem (opposite), with each pair occurring at an angle rotated 90° to the pair below it (decussate). There is no stipule (a small leaf-like structure at the base of the leaf stem), or stipules are small and sometimes fingerlike.

Flowers are usually showy, have radial symmetry (actinomorphic), and are born in head that are cymes or racemes, but can rarely be fasciculate or solitary. They are perfect (bisexual), with a synsepalous, five-lobed calyx united into a tube at the base. Inflorescences are terminal or axillary. Five petals are united into a tube with four or five epipetalous stamens. The style is expanded at the apex into a massive clavuncle just below the stigma. The ovary is usually superior, bicarpellary, and apocarpous, with a common fused style and stigma.

The fruit is a drupe, a berry, a capsule, or a follicle.

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